Tetralogy of Fallot (TOF) — #6 Pulmonary Valve: Valve-Sparing vs Transannular Patch

In contemporary TOF repair, the pulmonary valve (PV) decision is not simply “patch or no patch.” It is a lifetime RV outflow tract (RVOT) strategy that balances two competing goals: (1) immediate RVOT relief (avoid residual obstruction and RV hypertension) and (2) long-term RV protection (avoid chronic pulmonary regurgitation [PR] and RV volume overload). RVOT dysfunction—stenosis, regurgitation, or both—is nearly universal after TOF repair, so the operative plan should be framed as selecting the most durable and least morbid RVOT physiology for that child’s anatomy and growth trajectory. [1]

1) Core decision point: “Can the annulus be preserved?”

A. Valve-sparing (VS) repair — PV preservation (± limited PV intervention)

Typical selection

Favored when the pulmonary annulus is adequate, commonly using a practical Z-score around ≥ −2 as a starting reference (not an absolute rule). [2]

What you are buying (long-term bias)

Less PR and therefore less chronic RV volume loading, which is strongly linked to late RV dilation and downstream morbidity. [2,3]

What you are accepting

Some residual RVOT gradient may remain (often mild, sometimes moderate), particularly when obstruction is valve/annulus-level. Importantly, long-term data suggest that, when anatomy permits, accepting residual stenosis can be preferable to committing the patient to free PR, with better survival and fewer reinterventions compared with TAP in large cohort analyses. [3]

B. Transannular patch (TAP) — annular incision and patch augmentation

Typical selection

Chosen when annular hypoplasia would otherwise leave unacceptable post-repair RV pressure load, or when adequate relief cannot be achieved without opening across the annulus. [4]

What you are buying (immediate reliability)

Predictable annular-level RVOT relief, minimizing residual RV hypertension.

What you are accepting (chronic physiology)

In classic TAP, severe PR is expected, leading to chronic RV volume overload, progressive RV dilation, arrhythmia substrate, and a higher lifetime likelihood of PV intervention. [1,2]

2) Z-score is helpful—but not absolute (and “cutoffs” can mislead)

Z-scores provide a shared language, but their interpretation varies across datasets and calculators. This explains why “thresholds” differ between centers and publications. [4]

A practical way to use Z-score is:

Use Z-score to estimate risk, not to dictate the operation.
Decide based on (a) level(s) of obstruction, (b) leaflet morphology/mobility, and (c) predicted post-repair hemodynamics.
Recognize that delaying TAP until very low Z-scores may increase the risk of clinically significant residual gradients after attempted valve preservation. [4]

Evidence-based nuance (examples)

In valve-sparing repairs, an annulus Z-score around −1.3 can still produce a meaningful chance of a ≥30 mmHg residual PV gradient in some series—highlighting why “very low Z-score thresholds only” can be unsafe. [4]
Other cohorts identify increased early reintervention risk for residual stenosis when annulus Z-score drops below approximately −2.5 in certain valve-sparing strategies—supporting the common clinical “−2-ish” decision zone as a reasonable starting point, not a universal rule. [6]

3) A clean trade-off framework: pressure load vs volume load

If you spare the valve (VS)

Prioritizes: less PR → less RV volume load
Accepts: some RVOT gradient (often mild; sometimes moderate if still acceptable clinically) [3]

If you use TAP

Prioritizes: minimal gradient → minimal RV pressure load
Accepts: more PR → more RV volume load [1,2]

The key is to choose the dominant chronic burden—pressure vs volume—based on patient-specific anatomy and predicted growth.

4) Intraoperative “endpoint thinking” (what success looks like)

Valve-sparing pathway (a high-quality endpoint)

Infundibulum is generously relieved (myectomy/muscle bundle resection is complete).
PV leaflets are mobile after limited valvotomy/commissurotomy when appropriate.
Residual gradient is mild and acceptable, rather than chasing “zero gradient at any cost.” [3,5]

Classic and modern series emphasize that a valve-sparing strategy can be performed safely, with acceptable outcomes when hemodynamics remain favorable (e.g., avoiding a markedly high RV/LV pressure ratio). [5]

TAP pathway (a high-quality endpoint)

RVOT is fully relieved including annular level.
The team explicitly acknowledges that the patient has entered a PR-dominant physiology and structures follow-up accordingly. [1]

5) Contemporary refinements beyond the binary choice

Modern TOF programs increasingly use adjuncts to reduce the early penalty of TAP and/or expand the feasibility of valve preservation:

Valve-oriented strategies / structured preservation approaches (center-specific techniques and algorithms) have been reported to improve PV function preservation compared with traditional management in selected anatomies. [9]
Programs pursuing annulus-sparing approaches can reduce TAP utilization and are associated with less late RV dilation compared with TAP cohorts, without excessive reoperation risk in experienced hands. [8]
TAP + monocusp valve reconstruction: meta-analytic evidence suggests monocusp reconstruction can reduce PR severity and improve certain early postoperative outcomes, though durability is variable and long-term RVOT issues are not eliminated. [11]
Longitudinal institutional experience demonstrates an evolving practice pattern toward greater PV preservation/reconstruction, reflecting the field-wide bias: preserve competence when feasible, but not at the cost of prohibitive obstruction. [10]

6) Follow-up implications (why the intraoperative choice matters for decades)

Because RVOT dysfunction drives late morbidity, contemporary long-term management emphasizes structured surveillance, multimodality imaging (often including CMR), rhythm monitoring, and timely consideration of transcatheter or surgical pulmonary valve replacement when thresholds are met. [1]

References

[1] Geva T, Wald RM, Bucholz E, Cnota JF, McElhinney DB, Mercer-Rosa LM, Mery CM, Miles AL, Moore J. Long-Term Management of Right Ventricular Outflow Tract Dysfunction in Repaired Tetralogy of Fallot: A Scientific Statement From the American Heart Association. Circulation. 2024;150(25):e689-e707.

[2] Martins RS, Baulderstone KE, Raff GW, Kang N, Raees M, Bell D, Jivraj N, Mulholland J, Mullett CJ, Bigam DL. Comparing clinical and echocardiographic outcomes following valve-sparing versus transannular patch repair of tetralogy of Fallot: a systematic review and meta-analysis. Interdiscip Cardiovasc Thorac Surg. 2024;39(1):ivae124.

[3] Blais S, Marelli A, Vanasse A, Dahdah N, Dancea A, Drolet C, Dallaire F. Comparison of Long-term Outcomes of Valve-Sparing and Transannular Patch Procedures for Correction of Tetralogy of Fallot. JAMA Netw Open. 2021;4(7):e2118141.

[4] Awori MN, Leong W, Artrip JH, O'Donnell C. Tetralogy of Fallot repair: optimal z-score use for transannular patch insertion. Eur J Cardiothorac Surg. 2013;43(3):483-486.

[5] Stewart RD, Backer CL, Young L, Mavroudis C. Tetralogy of Fallot: results of a pulmonary valve-sparing strategy. Ann Thorac Surg. 2005;80(4):1431-1438.

[6] Hofferberth SC, Nathan M, Marx GR, Lu M, Sleeper LA, Marshall AC, Baird CW, Mayer JE, del Nido PJ, Emani SM. Valve-sparing repair with intraoperative balloon dilation in tetralogy of Fallot: Midterm results and therapeutic implications. J Thorac Cardiovasc Surg. 2018;155(3):1163-1173.e4.

[7] Stephens EH, Wolfe BL, Talwar AA, Patel A, Camarda JA, Eltayeb O, Monge MC, Forbess JM. Applicability and Durability of Valve-Sparing Tetralogy of Fallot Repair. World J Pediatr Congenit Heart Surg. 2021;12(5):628-634.

[8] Hickey E, Merlo M, Moon MR, et al. Annulus-Sparing Tetralogy of Fallot Repair: Low Risk and Benefits to Right Ventricular Geometry. Ann Thorac Surg. 2018;105(3):851-859.

[9] Sen DG, Najjar M, Yimaz B, Levasseur SM, Kalessan B, Quaegebeur JM, Bacha EA. Aiming to Preserve Pulmonary Valve Function in Tetralogy of Fallot Repair: Comparing a New Approach to Traditional Management. Pediatr Cardiol. 2016;37(5):818-825.

[10] Schulte LJ, Miller PC, Bhat AN, Carvajal-Dominguez HG, Chomat MR, Miller JR, Nath D, Eghtesady P. Evolution of Pulmonary Valve Management During Repair of Tetralogy of Fallot: A 14-year Experience. Ann Thorac Surg. 2023;115(2):462-469.

[11] Wei X, Li T, Ling Y, Chai Z, Cao Z, Chen K, Qian Y. Transannular patch repair of tetralogy of Fallot with or without monocusp valve reconstruction: a meta-analysis. BMC Surg. 2022;22(1):18.